Sound absorption material refers to the material that can absorb the incident sound under the action of its porosity, thin film or resonance, and can be divided into porous sound absorption material and resonance sound absorption structure based on its physical property and sound absorption way. The structural feature of porous sound absorption material is that there are a large number of interconnected and outward micropores in the material, and its sound absorption principle is that the entry of sound wave into the material pore will vibrate tiny fibers of air and material in the pore, and result in friction and viscous resistance, and sound energy is converted into heat energy and absorbed. Fiber material and plaster material are widely used in the engineering, in which the former includes glass wool, mineral wool or various sound absorption boards or sound absorption components mainly made from such materials; the latter includes microporous brick and particulate slag sound absorption brick.
Porous plaster sound absorption material has many varieties, and is divided into slag sound absorption brick, expanded perlite sound absorption brick, pottery clay sound absorption brick and environmentally-friendly sandstone sound absorption board, etc. due to the difference of raw materials. Although the said sound absorption material has many varieties, such materials are not widely applied for its low porosity, low sound absorption coefficient and unsatisfactory sound absorption effect due to the limitation of manufacturing method, pore-forming mechanism and structure strength. For example, the patent (application no.: 201210398344.3) discloses an environmentally-friendly sandstone sound absorption board which is that natural round sand or natural colorful round sand and epoxy resin glue are pressed as the board after mixture to form the base layer, and expanded perlite particle and epoxy resin glue are pressed on the board after mixture to form the light material layer on which the gridding cloth is pressed to act as tensile strength and skeleton. The said sound absorption board is composed of four-layer structure, i.e. base layer, light material layer, gridding cloth layer and decoration surface layer, and featured by complicated structure, plenty of manufacturing processes and high cost. The pore-forming mechanism of base layer and light material layer in the environmentally-friendly sandstone sound absorption board is that the natural pore arising from the evaporation of water molecule and the curing of epoxy resin glue plays a role in sound absorption. Since the pore arising from the evaporation of water molecule is intermittent and random, the porosity is unpredictable, and most of pores arising from the evaporation of water molecule are closed pores that can't ventilate and store air. Such closed pore does not have sound absorption function, so its sound absorption coefficient is uncertain, and sound absorption effect is unsatisfactory. The dosage of binding agent is increased with the increase in specific surface area between sands due to the irregularity of external surface of the sand, so the cost of the said sound absorption board remains high, and its promotion and application are also affected.
The shortcomings above still need to be improved.